Abstract: By utilizing the HYSCANⅡhydrogen analyzer to measure the hydrogen content of every experimented melt based on the theory of pressure reduced test, the effect and functionary mechanism of ultrasonic vibration on the degassing process of 7050 aluminum melt are studied by introducing ultrasonic at different ultrasonic power, frequency offset, temperature range through the vibration-transfer tool rod. Experimental results show that the porosities of casting ingot treated by ultrasonic are reduced significantly. The hydrogen content of the melt is gradually reduced with the increase of ultrasonic power. The effect of degassing in the resonance condition is much better than that in the non-resonance condition. The efficiency of degassing between 700 ℃ and 720 ℃ is much greater than that between 640 ℃ and 660 ℃. The cavitation effect plays a key role in producing numerous cavity bubbles. At the same time, the “area” effect and the “shell” effect of the cavitation bubble play a decisive role in the degassing process.

Key words: Cavitation effect, Degassing, HYSCANⅡhydrogen analyzer, Ultrasonic frequency offset, Ultrasonic power